Caterpillar of the day - Ceratomia amyntor (Sphingidae)

This species is better known as the Elm Sphinx or the Four-horned Sphinx. The first name relates to the caterpillar's diet (elm trees, but also birch, basswood, and cherry). It's second, more bad-ass, name comes from the 4 horn-like projections the protrude from the anterior end (i.e., not including the anal horn that characterizes sphingid larvae). Like many sphingids, at the end of the caterpillar life-stage they head down to the base of its host plant and pupate underground. Here is a photo of a late instar C. amyntor caterpillar:

Looks to me like this guy would be incredibly cryptic on those big elm leaves. Apparently, there is some variation in the colour of these larvae, including brown, orange, and pink-brown. Curiously, the oblique stripes seem to match the venation pattern of the foliage, perhaps enhancing crypsis.